Loading Gmax 165 question

[Philthy1]

Looking at the Hodgdon site for 165g 30-06 data------For IMR 4064 and I see the Sierra spbt at 49-52.5 gr. and the Hornady gmx at 44.4-48.2

Why the huge difference? Out of curiousity, what am I missing here?

 

[huntingfamily]

Hornady manual says 51.9 grs max for IMR4064.
There can be quite a bit of variation in manuals. It's based on the components and firearms they used at the time.

 

[Lefty Dick]

GMX’s have a pile of bearing surface, and result in increased pressures because of this. Hence the lower loads.

 

[shotgun64]

In my 30/06 I was shooting 50gr. 4064 with Hornady BTSP with fed 210 primers.
It was a very accurate load, did not chrono.
This was out of a Remington Stainless.
One thing strange out of this factory gun, is that it was freebored. You could not come close to the lands, but super accurate for a factory.
Bullets at 100 yards were always touching...

 

[Philthy1]

The large bearing surface was also my guess. Also, this load is for a zg47, which have super long throats. So I will have to do some experimentation.